Records of deep-sea rhizopod tests inhabited by metazoans in the North-east Atlantic

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Abstract
The tests of more than 16000 large, benthic foraminifers (mainly the straight, tubular ammodiscaceans Bathysiphon folini and B. rusticus but also hormosinids and calcareous species) and xenophyophores from epibenthic sledge samples obtained between 996 and 4 416 m were examined for metazoan inhabitants. The 1 011 organisms recorded were dominated by sipunculans but also included nematodes, polychaetes, harpacticoid copepods, isopods, amphipods, tanaids, and hydroids. Eggs were observed, either alone or associated with sipunculans, nematodes, amphipods, and a tanaid. Sipunculan and other worms occupied 11 % of Bathysiphon tubes and = 20 % of Hyperammina tubes in some samples. In contrast, calcareous tests were rarely inhabited by metazoans. Data from several bathyal core samples indicate that a few (about 4 %) of the meiofaunal organisms were living in small foraminiferal tests, usually those of globigerinaceans. Most of the metazoans were found inside empty tests which apparently served as refuges. However, juvenile lysianassid amphipods (Aristias sp.) appear to be predators or parasites of the large, agglutinated foraminifer Hyperammina palmiformis. The amphipods enter live tests and consume the protoplasm.